Mod Podge

I love this stuff. It creates a nice shiny finish for decoupage with minimal effort, it also works nicely to seal paper art projects like layered paper pins. The glossy finish is my favorite because of the durable shine but the matte is also wonderful for projects that you don’t want to be shiny.
Just apply thin coats, and let them dry 20 minutes before adding another coat. I usually do single coats for light weight projects, and 4 or 5 coats for anything that will see a lot of use. It’s water-based so clean up is very easy while it’s still wet.
It’s a classic.